In a field-induced magnetic random access memory (MRAM) a current-induced magnetic field generated around metal lines is used to write data into memory cells. Each memory cell stores a bit of data in a magnetic tunnel junction (MTJ). The MTJ is located at the intersection of two conductors in the form of a bit line and a word line. Normally, these lines are laid out perpendicular to each other. To write binary data (a “0” or a “1”) to a MTJ cell, enough current must flow simultaneously through the bit line and the word line associated with that particular cell for a certain amount of time. The sense in which the current flows in both metal lines sets the data value “0” or “1” in the cell.
In some embodiments of MRAM, data may be read from an MTJ through an access transistor connected to the MTJ, which forms part of the memory cell. This transistor is unique to the MTJ being addressed but parts of the transistor may be shared with transistors from neighboring cells.